OUTLINE: This is a randomized, crossover study. Patients are randomized to one of two treatment arms. Arm I: Patients receive oral Ro 31-7453 under fasting conditions on day 1. After a 1-week washout period, patients receive oral Ro 31-7453 under fed conditions. Arm II: Patients receive fed treatment as in arm I on day 1. After a 1-week washout period, patients receive fasted treatment as in arm I. Both arms: At the start of week 3, patients may continue to receive oral Ro 31-7453 every 12 hours on days 1-4. Treatment repeats every 3 weeks for at least 24 weeks in the absence of disease progression or unacceptable toxicity. Patients are followed at 7 days.